The Steam Page for Quantum Conundrum now features a demo for this puzzle game from Airtight Games and Portal originator Kim Swift (thanks PC Gamer). Here's the premise of the game:

When you, as a young boy, are dropped off to visit your uncle, you notice something’s wrong. First, he’s not there to greet you. Second, there’s the explosion that happened right as you arrived. And third, the house seems to be even weirder than you remembered it. Now, your job is to find—and ultimately rescue—your uncle, by using his newest invention, the Interdimensional Shift Device (or IDS), to switch between dimensions and solve puzzles. That sofa too heavy to move? There’s a dimension for that! Switch to Fluffy Dimension and that sofa is now light as a feather. Need to get up to a high ledge? There’s a dimension for that! Just switch to Anti-Gravity Dimension and things begin to float upward. Need to make things heavier? There’s a dimension for th—well, you get the idea. Switch dimensions in real time, work your way through the crazy complex mansion wings and rescue your uncle!